1. Field of the Invention
This invention relates to an arrangement for reproducing a charge representing an analog level without perturbing the original charge, and, more particularly, for reproducing the charge representative of an analog level in a charge transfer circuit of the type known to the art as a bucket brigade device (BBD).
2. Description of the Prior Art
U.S. Pat. No. 3,806,772 issued Apr. 23, 1974 to J. M. Early entitled CHARGE COUPLED AMPLIFIER and assigned to the Fairchild Camera and Instrument Corporation describes a charge amplification system incorporating a plurality of amplification stages embodied in charge-coupled device technology.
In the Early patent a first packet of charge is used to create a second packet of charge, however, the second packet of charge is not stated to be a duplicate or replica of the first charge packet. The Early patent also does not employ bucket brigade technology.
Attention is also directed to copending U.S. patent application, Ser. No. 625,425 filed Oct. 24, 1975 by L. G. Heller entitled A METHOD AND APPARATUS FOR REPLICATING A CHARGE PACKET and which is assigned to the present assignee. In this application a first charge packet is precisely duplicated by a charge coupled device circuit wherein the first charge packet tends to reduce a reference voltage by a corresponding value. This causes a corresponding diffusion current to flow and create a second charge packet which is identical to the first charge packet. This application is distinct in structure from the bucket-brigade device of the present invention.